Help me?

Not here to get thumbs I just need a little help. I'm looking for a link to a story. I can't remember if it's a true story or not.

It's the one about the scientist that took acid or LSD or some form of hallucination based drug and had a trip that made him think he was living with a tribe. (Mayans/Indians?)
And so he went on to learn the language of these people so that he could take the drug again and be able to communicate with them.